Flame spheroidisation of dense and porous Ca2Fe2O5 microspheres

Jesús Molinar Díaz; Sabrin Abdus Samad; Elisabeth Steer; Nigel Neate; Hannah Constantin; Md Towhidul Islam; Paul D Brown; Ifty Ahmed

doi:10.1039/D0MA00564A

Flame spheroidisation of dense and porous Ca₂Fe₂O₅ microspheres†

Jesús Molinar Díaz,

^a Sabrin Abdus Samad,^a Elisabeth Steer,^b Nigel Neate,^bc Hannah Constantin,^c Md Towhidul Islam,^ad Paul D Brown^ab and Ifty Ahmed*^a

Author affiliations

* Corresponding authors

^a Advanced Materials Research Group, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, UK
E-mail: ifty.ahmed@nottingham.ac.uk

^b Nanoscale and Microscale Research Centre, University of Nottingham, University Park, Nottingham NG7 2RD, UK

^c Department of Mechanical, Materials and Manufacturing Engineering, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, UK

^d Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering, Noakhali Science and Technology University, Noakhali 3814, Bangladesh

Abstract

Compositionally uniform magnetic Ca₂Fe₂O₅ (srebrodolskite) microspheres created via a rapid, single-stage flame spheroidisation (FS) process using magnetite and carbonate based porogen (1 : 1 Fe₃O₄ : CaCO₃) feedstock powders, are described. Two types of Ca₂Fe₂O₅ microsphere are produced: dense (35–80 μm), and porous (125–180 μm). Scanning electron microscopy (SEM) based techniques are used to image and quantify these. Complementary high-temperature X-ray diffraction (HT-XRD) measurements and thermogravimetric analysis (TGA) provide insights into the initial process of porogen feedstock decomposition, prior to the coalescence of molten droplets and spheroidisation, driven by surface tension. Evolution of CO₂ gas (from porogen decomposition) is attributed to the development of interconnected porosity within the porous microspheres. This occurs during Ca₂Fe₂O₅ rapid cooling and solidification. The facile FS-processing route provides a method for the rapid production of both dense and porous magnetic microspheres, with high levels of compositional uniformity and excellent opportunity for size control. The controllability of these factors make the FS production method useful for a range of healthcare, energy and environmental remediation applications.

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Article information

DOI: https://doi.org/10.1039/D0MA00564A
Article type: Paper
Submitted: 03 Aug 2020
Accepted: 13 Nov 2020
First published: 18 Nov 2020
This article is Open Access

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Mater. Adv., 2020,1, 3539-3544

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Flame spheroidisation of dense and porous Ca₂Fe₂O₅ microspheres

J. Molinar Díaz, S. A. Samad, E. Steer, N. Neate, H. Constantin, M. T. Islam, P. D. Brown and I. Ahmed, Mater. Adv., 2020, 1, 3539 DOI: 10.1039/D0MA00564A

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